Identity Conference 2008

I'm attending this conference (final day today). A couple of themes fired for me - both from Dick Hardts presentation, - but definitely "under the hood" of several sessions:

• What is Open Data - is it like Eric Schmidt's 'the data is in the cloud' ?
  I found a few links to the topic of Open Government Data
  
• What is rel='me' (Dick Hardt mentioned this)? Does this relate to the Semantic Web?

I'm hoping to spark some discussion on this today - let's see who's also into this stuff :). I've tagged several relevant sites, see imconf, opendata and opengovernment

semweb on youtube

Here are a couple of introductory vids fom Matt Sporny.

By Matt Sporny

Some 'good oil' on python default arguments

Traps and a simple way to avoid-em for python using mutable types as default arguments - well worth a read

http://boodebr.org/main/python/tourist/mutable-obj-as-default-arg

"Many modern languages allow for default function arguments. Default arguments can be a great thing - they allow you to use sensible defaults for the common cases, without taking away the power to add more functionality as needed. You can arbitrarily expand a function definition without breaking existing code by providing sensible defaults for the new parameters.

Here is a fun example of how Python will bite you if you try to use a mutable object (like a list, dict, or object instance) as a default argument. The following is an example function I'm trying to write ..."

A metadata registry in action

I found this today while exploring use cases for the skos ontology looking for similarities to those for the cvcore. The NSDL Metadata Registry has some interesting features:

• it's based on skos
• it demonstrates a nice simple approach to the slowly-changing-time dimension , using a timeslice mechanism that allows the user to get a point-in time view of a resource.
• all resources are viewable as either HTML or RDF
• The developer blog gives an interesting insight into how the project runs.
  

Well worth a look for my NZ education sector friends :)

Importing FOAF / SKOS ontologies with Protege OWL

I''ve been having some tribulations with importing the well-known ontologies (FOAF and SKOS) properly in Protege 3.4 (build 108)

First problem - what to import?
Simple question, but no immediately obvious answer. BTW has something changed here recently - as I seem to remember this being simple in the past??

I'm now importing OK from...

• SKOS: http://www.w3.org/2004/02/skos/core/owl-dl/skos-core-owl-dl.owl
• foaf:
  http://xmlns.com/foaf/spec/index.rdf

Second Problem - Protege errors
I wouldn't expect too much drama here as these are well travelled paths?

foaf won't import...

INFO: Loading triples
INFO: Start processing ontology: http://xmlns.com/foaf/spec/20070524.rdf Time: Thu Apr 03 11:42:43 NZDT 2008
WARNING: [ProtegeOWLParser] Warning: No default namespace found in file. Will use http://xmlns.com/foaf/spec/20070524.rdf -- DefaultProtegeOWLParserLogger.logWarning()
INFO: [ProtegeOWLParser] Completed triple loading after 646 ms
INFO: [TripleChangePostProcessor] Completed lists after 0 ms
java.lang.ClassCastException: edu.stanford.smi.protegex.owl.model.impl.DefaultRDFSNamedClass
at edu.stanford.smi.protegex.owl.model.triplestore.impl.OWLAnonymousClassPostProcessor.convertNamedEnumeratedClasses(Unknown Source)
at edu.stanford.smi.protegex.owl.model.triplestore.impl.OWLAnonymousClassPostProcessor.(Unknown Source)
at edu.stanford.smi.protegex.owl.model.triplestore.impl.TripleChangePostProcessor.postProcess(Unknown Source)....
...lots more

Curious that I get different behaviour (on my OSX leopard system) depending on how I start Protege.

• from the protege.app the ontology loads, but the properties tab is broken (red box)
• from run_protoge.sh I get the error output above and the ontology doesn't load

Ok, I checked the latest build (128) and I get almost the same behaviour.

And finally protege 4.0 (alpha) build 61, which Does work - however it's a completely new UI experience.